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The Perseid Meteors

Royal Greenwich Observatory
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Short Special Information Leaflet No. 4: 'The Perseid Meteors'

The Perseids:

One of the most prolific meteor showers is the Perseids. The radiant is in the constellation Perseus, and meteors from this shower can be seen over a period of about 3 weeks centered on August 12.
In good years up to 70 meteors an hour can be seen near the peak.

This meteor stream is associated with Comet Swift-Tuttle, which passed close by the Sun in 1992.
As the meteors in the stream are thought to be dust particles released from the comet, it is thought likely that there is a dense stream of such particles in the path of the comet and located close to it.

The last time (1993) that the Earth passed through the comet's orbit just after the comet had been close to the Sun, there was a radical increase in the number of meteors seen, rising to about 300 an hour. It is thus likely that when the Earth passes through the comet's path on August 12, there may be a very high peak in the number of meteors seen.
The peak could well be only an hour long, and the exact time of the Earth passing through the maximum is only poorly known, and so it will be worth keeping a lookout from about midnight onwards, always assuming that the skies are clear!

Produced by the Information Services Department of the Royal Greenwich Observatory.

PJA Wed May 8 10:44:36 GMT 1996

webman@mail.ast.cam.ac.uk

ARVAL's Note:

The Perseids have become the most exciting meteor shower in recent years, producing hourly rates of around 300 in 1993, 220 in 1994, 160 in 1995, and around 140 in 1996, at the shower's primary maximum, which this year is expected to fall around 06h UT on August 12.

The return of the Perseids' parent comet Swift-Tuttle in late 1992 was almost certainly responsible for producing this recent increase.

Whether the Perseid peak will continue the decreasing trend in the primary maximum's rates remains to be seen, but conditions are reasonable for trying to cover the 1997 event, as the waxing gibbous Moon will set just before midnight for most northern hemisphere observers on August 11, and by then the shower radiant will be at a good elevation.

Information from the 1997 Meteor Shower Calendar of the International Meteor Organization (IMO)

Comet Swift-Tuttle was discovered independently by Lewis Swift and Horace Tuttle in 1862. The comet has an orbital inclination of 113° and a period of about 128 years. It was associated with the Perseids meteor shower by Giovanni Schiaparelli in 1862. (1)

The Perseids is one of the most consistent and active showers, and has a proven double peak, with a short outburst a number of hours prior to the main maximum. (2)

The radiant of the Perseids is at R.A. 03h 04m, +57° (3)

Also called "The Tears of St. Lawrence", whose feast day, August 10, used to coincide with the shower's maximum in the 18th and 19th centuries. Precession gradually moved the Perseids' maximum to August 11 in the 1890's, and now more often to August 12.
Short Perseids outbursts have occurred from 1991 to 1996. (3)

Sources:
(1) The Facts on File Dictionary of Astronomy. Edited by Valerie Illingworth.
(2) Observer's Handbook 1997. The Royal Astronomical Society of Canada.
(3) Astronomical Calendar 1997. The Department of Physics, Furman University in cooperation with the Astronomical League.

Updated: May 21 '97, October 14 '08, June 24 '14

Best seen with Font Verdana.
See About the Web Pages of Observatorio ARVAL.

See Perseid Trail (NASA/GSFC Astronomy Picture of the Day, 2008 August 14)

For some illustrative images and excellent texts, link to: Meteoroids and Meteorites in Calvin J. Hamilton's Views of the Solar System

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